Historically, snipers are a persistent military and security problem. Current snipers are becoming more lethal at longer ranges due to increased training and improved equipment. The increased engagement range reduces the probability of detection and generally allows a sniper to inflict a casualty before he is detection. This single shot casualty of a high-value target is often sufficient to achieve the sniper's objective and there is often no intent to fire a second round.
There are various technologies available for detecting a sniper after a first shot is fired and detecting the source of incoming mortar rounds or other ballistic projectiles. One method is to detect the projectile in-flight, be it a sniper bullet or a mortar round, and track its ballistic trajectory in flight. From a series of measurements of a projectile's location while it is in ballistic flight, the location of the weapon from which it originated can be estimated. Alternatively, the projectile's trajectory can be estimated from acoustic signals associated with the movement of the projectile in air again allowing one to compute the location of the weapon from which the projectile originated.
Methods for detecting and tracking projectiles utilize optical, microwave radar, and acoustic methods. However, independent of the detection and tracking modality, these methodologies require that a projectile be fired by an adversary before the detection can occur.
There are also several less well known methods for detecting a sniper before he shoots. Physical Optics Corporation (POC) of Torrance, Calif. proposed in 2007 to develop a new Pre-shot Sniper Detection (PSD) system that identifies covert snipers before they shoot, even in cluttered urban environments, in less than 2 to 3 seconds. The PSD system is based on a multimodal, high-resolution, imaging optics package with no moving parts and processing hardware that accurately detects snipers. Argon Engineering of Fairfax, Va. advertises an optical pre-shot sniper detection system with no specifications listed. Torrey Pines Logic, Inc. of San Diego, Calif. sells an optical retro-reflection system (pre-shot sniper detection), the Mirage 1200™ Beam 50. US patent application No. 2008/0259320A1, dated Oct. 23, 2008, entitled “Apparatus and Method for Detecting Optical Systems in a Terrain” discloses an apparatus that utilizes an active laser (light) illuminator of terrain and analysis of the returned signal to detect the presence of sighting optics associated with a sniper.
There remains an urgent and unsatisfied need for non-optical based pre-shot sniper detection as demonstrated by the advanced planning briefing for Industry presented 26 Jan. 2010 by the Combating Terrorism Technical Support Office.
There is also a need for effective pre-engagement detection of snipers because a single shot casualty of a high-value target is often sufficient to achieve the sniper's objective and there is often no intent to fire a second round. Pre-engagement detection of snipers provides a proactive ability to eliminate or significantly reduce the threat of snipers by notifying the potential victim of the presence and location of a sniper before the sniper shoots. However, each of the technologies discussed above has deficiencies in achieving reliable pre-shot sniper detection. Each of the discussed technologies either suffer from optical limitations or temporal limitations. What is needed is a technology capable of detecting a sniper's weapon before a shot is fired without optical limitations.